A common type of instrument is one in which a sensor produces a signal whose frequency is related in some functional way, often nonlinear, to a physical input variable. In order to use such a sensor in a digital system, the frequency of the sensor signal must be converted into a series of digital samples. The simplest and most straightforward way to measure frequency is to count cycles of the sensor or input signal for a known time interval. However, for many applications, the resolution produced by such a technique is far too low, unless unacceptably long time bases are used. While more complex techniques have been used to increase resolution, many of such prior techniques do not provide continuous data capture, real time processing, or synchronization of the data to a sampling frequency.